Hydraulic power unit



Feb. 27, 1934. B, WALKER 1,948,951

HYDRAULIC POWER UNIT Filed Aug. 21. 1929 INVENTOR. Baum waif-u:

A TTORNEYS.

Patented Feb. 27, 1934 UNITED STATES 1,948,951 HYDRAULIC POWER UNIT Brooks Walker, Application August 21, 1929.

3 Claims.

This invention relates to hydraulic operating units for operating parking devices such as disclosed in my United States Letters Patent No. 1,693,288 issued November 27th, 1928.

In this prior patent I have disclosed a parking mechanism operative to elevate the end or a vehicle and then shift the vehicle laterally. To operate this mechanism 1 provide a hydraulic power unit including a pump and a hydraulic cylinder within the latter of which is a piston connected to the parking device so that reciprocation o! the piston will raise or lower the parking device. The stroke of the piston is predetermined and movement thereof is automatically discontinued at the end of each stroke.

It is the principal object of the present invention to provide improved apparatus for reciprocating an operating member sure, which mechanism maintains the opposite strokes of said member equal and automatically discontinues its movement at the end 01 each stroke, to provide a single motion control for a clutch and reversing valve that can be located remote from the actuating cylinder.

In the present instance forms of apparatus for accom These mechanisms all include a cylinder with a double acting piston which is to be reciprocated The pistonof course is The pressure in the cylinder operating in a closed fluid circuit so that it exhausts at one end of the piston while injecting at the other end of the piston. An automatic control is provided which renders the pump ineffective in operating the piston at the end of each piston stroke.

The apparatus disclosed herein is primarily intended for operating vehicle parking devices such as previously referred to, but I am aware that it is susceptible of other uses, such as operating elevator doors and like devices.

The invention is exemplified in the following description and illustrated by way of example in the accompanying drawing, in which:

Figure 1 is a diagrammatic view of a hydraulic power unit which is electrically controlled,

Figure 2 is a view or a hydraulic power unit in which the pump is electrically controlled through the medium or a magnetic clutch.

Referring more particularly to the accompanying drawing; in Figure 1 I have shown an electrical gear pump which is automatically controlled so that when the circuit through the gear pump is established the unit will be placed in opera- Piedmont, Calll.

Serial No. 387,392

tion and will operate the piston. when the piston reaches the end of its stroke the circuit through the gear pump is automatically broken so as to discontinue the operation of the pump.

Referring to this figure, 23 indicates a gear 00 pump of any preferred design which is motor operated. lhis gear pump is connected by means of pipes 24 and 25 to the opposite ends of the cylinder 10. The circuit for this gear pump includes a battery 26 which is connected by means of a conductor 2'! to one terminal of a switch 28. This switch is of the double throw type as it is adapted to cooperate with contacts 29 and 30.

A conductor 31 connects the contact 29 to the terminal of a switch 33. The switch arm 33 is connected by means of the conductor '34 to a solenoid magnet 35 and thence to the ground 36 by a conductor 3'1. Thus when the switch 33 is closed a circuit will be established to energize the magnet 35. The core of this magnet is connected with a double throw switch 38. The switch 38 is pivoted at its center and resiliently held in the center position as shown by the centering springs attached thereto. As the magnet is energized this switch will be placed in contact 30 with a terminal 39 electrically connected to the motor of the gear pump 23, the other terminal of the motor being connected by means 01 a conductor 40 to the groun The motor will then operate until the piston has moved to the full a length or its stroke. Upon reaching the end of its stroke, a switch actuator 41 on the end of the piston rod will engage the switch 33 and open it, thus opening the circuit through the motor of the gear pump and discontinue its operation.

To again place the cylinder in operation to actuate and move said piston through its return stroke, the switch 28 is operated and placed in contact with the contact 30 which causes the current from the battery to flow through the conductor 27 through a conductor 42 to a switch 43 which is similar to the switch 33. A conductor 44 is connected with the switch 43 and with one side of a solenoid magnet 46, the other side which is connected by a conductor 4'? to the ground. This latter magnet 46 is arranged coaxially with the magnet 35 and they are provided with a common core, which is as previous- 1y described connected to the double throw switch 38. When the magnet 46 is energized the switch arm 38 is placed in contact with the contact 48 which is connected to the motor of the pump 23. This flow oi the current through the second circuit will cause the motor o! the gear pump 1 23 to reverse and drive the latter in the opposite direction which reverses the fluid circuit and causes the piston to return to the opposite end of its stroke. Upon reaching the end oi its stroke a circuit breaker 41a on the piston rod 43 which disengages the solein turn allows the centering spring arm to open the contact between the circuit of the motor or the as to discontinue its operation. the piston is shown at one end oi its stroke with the switch 33 closed and the switch 38 open, when the piston is at the opposite end 01 its travel the switch 33 is opened to terminate the piston travel in that direction.

In Figure 2 the gear pump 16 is connected with a power source through the medium of a magnetic clutch 50. The cylinder 10 is closed by ends 11 which carry stufiing glands 12 to seal 38 and 48 of gear pump so In Figure 1 These ports are controlled by a valve 53 so that although the pump is driven time the valve alternately changes 55 adapted to cooperate with contact points 56 and 5'7. The valve shaft 54 is revolved through the medium of a hand lever the magnetic clutch 50.

To move the piston in the lever 58 is manipulated the pipes 51 and 52 and at the same time connect the contact points 57 through the medium of the switch arm 55 so as to estabthe battery through the switch 5% thence through the magnetic clutch 50 to the ground. When this circuit is established the magnetic clutch will be engaged causing the gear pump to operate and exhaust fluid from one end of the cylinder while injecting it into the other.

the gear pump.

To compensate for any leakage, I may desire to provide a fluid reservoir '70 which is connected to the pipe 51 by means of a pipe 71. This pipe 71 includes an interposed check valve 72 which permits fluid to be withdrawn from the reser- Patent No. 1,948,951

BROOKS voir into the fluid circuit but prevents fluid from the circuit from being returned to the reservoir.

From the foregoing it is obviousthat I have operating said pump. tuated clutch for forming a connection between 3. A hydraulic operated unit including a cylinder, a piston reciprocally mounted therein, a fluid BROOKS WALKER.

Granted February 27, 1934 WALKER The above entitled patent was extended July 24 1951, under the provisions of the act of the original term thereof.

of June 30, 1950, for 6 years and 214 days from the expiration Commissioner of Patents.

23 to reverse and drive the latter in the opposite direction which reverses the fluid circuit and causes the piston to return to the opposite end of its stroke. Upon reaching the end oi its stroke a circuit breaker 41a on the piston rod 43 which disengages the solein turn allows the centering spring arm to open the contact between the circuit of the motor or the as to discontinue its operation. the piston is shown at one end oi its stroke with the switch 33 closed and the switch 38 open, when the piston is at the opposite end 01 its travel the switch 33 is opened to terminate the piston travel in that direction.

In Figure 2 the gear pump 16 is connected with a power source through the medium of a magnetic clutch 50. The cylinder 10 is closed by ends 11 which carry stufiing glands 12 to seal 38 and 48 of gear pump so In Figure 1 These ports are controlled by a valve 53 so that although the pump is driven time the valve alternately changes 55 adapted to cooperate with contact points 56 and 5'7. The valve shaft 54 is revolved through the medium of a hand lever the magnetic clutch 50.

To move the piston in the lever 58 is manipulated the pipes 51 and 52 and at the same time connect the contact points 57 through the medium of the switch arm 55 so as to estabthe battery through the switch 5% thence through the magnetic clutch 50 to the ground. When this circuit is established the magnetic clutch will be engaged causing the gear pump to operate and exhaust fluid from one end of the cylinder while injecting it into the other.

Patent No. 1,948,951

BROOKS WALKER The above entitled patent was extended of June 30, 1950, for 6 years sions of the act of the original term thereof.

voir into the fluid circuit but prevents fluid from the circuit from being returned to the reservoir.

From the foregoing it is obviousthat I have operating said pump. tuated clutch for forming a connection between 3. A hydraulic operated unit including a cylinder, a piston reciprocally mounted therein, a fluid BROOKS WALKER. Granted February 27, 1934 July 24 1951, under the proviand 214 days from the expiration Commissioner of Patents.

' Patent No. 1,948,951 Granted February 27, 1934 BROOKS WALKER The above entitled patent was extended J uly 24 1951, under the provisions of the ant of June 30, 1950, for 6 years and 214 days from the expiration of the original berm thereof. 

